(a) Field of the Invention
The present invention relates to a location based vehicle multihop protocol (VMP)-unicast apparatus for two vehicles out of a communication zone to perform a unicast communication by using a multihop routing function in a vehicular ad-hoc network (VANET) and a routing method using the apparatus.
(b) Description of the Related Art
Topology is rapidly changed in a communication environment between vehicles unlike a network environment. Therefore, it is difficult to consistently maintain a routing path up to a destination of the vehicle. As a result, a node to which data will be forwarded is should be designated according to the situation on the basis of location information of the destination.
Greedy perimeter stateless routing (GPSR) is generally used among unicast routing algorithms based on the location information. The GPSR is a routing algorithm in which assumed that the location of the destination node is known, a node among nodes in the communication zone, which is close to the destination node is selected and a packet is forwarded to the selected node.
The GPSR may be smoothly operated under a condition without an obstacle like an expressway. However, when the node close to the destination node is just selected as the forwarding node in the state in which communication is invalid due to surrounding buildings like an urban environment, the packet may not be transferred to the destination.
Greedy perimeter coordinator routing (GPCR) is a routing algorithm developed to overcome the problem of the GPSR. When a node at an intersection is set as a coordinator and the packet is forwarded to the coordinator, the packet may be transferred to the destination even though a line of sight (LOS) is not secured due to the building like an urban.
However, in the case of the GPCR, when the nodes at an intersection are selected as the coordinator, traffics are concentrated on the nodes, such that the packet may not be normally transferred.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.